What is subject word disagreement?

words are not agreeing

Explanation:

I have one banana. (this is subject agreement)

I has one banana. (this is subject disagreement)

Subject-verb agreement is when the subject and the verb agree in number/plurality and Subject-verb disagreement is just the opposite of it. That means it is when the subject and the verb does not agree in number/plurality.

Example:

"I are playing "

We was supposed to put "am" instead of "are".

In this sentence, we used plural noun with a singular verb.